Segments for articulated arms are known, made of metal material, which are reciprocally hinged at the respective ends and to which actuation members are associated, for example by means of brackets.
The actuation members provide to articulate one segment with respect to the other, to take them into at least a first extended or working configuration, in which they reach a desired operating position, and a second folded configuration in which the segments are folded one with respect to the other to assume a condition of minimum bulk, usually in the transport condition.
It is also known that, to reduce the overall weight of the articulated arms, the segments are made of composite material, for example comprising carbon, glass or aramidic fibers or similar, which are drowned in a binding resin.
It is also known that, when the articulated arms are in use, the segments are subjected to great stresses and vibrations and it is therefore necessary to correctly size and configure the sections of the individual segments so as to satisfy the requirements of safety and mechanical resistance.
In particular, it is known that the most stressed zones are the reciprocal hinging points between the individual segments, and also the zones where the actuation members are pivoted.
It is known that, with regard to segments made of metal material, the attachment zones are obtained by attaching, usually by welding, to the longitudinal body of the segment, one or more flanges provided with holes in which the actuation members are pivoted. In known solutions of segments made of composite material, it is known to provide that this zone is always made of metal material. In this case, solutions are known which provide to make of metal material a tract of the longitudinal body of the segment, which tract is subsequently incorporated during the step of making the segment of composite material. Said tract of metal material is in turn provided with attachment zones for the actuation members, for example consisting of brackets welded thereto.
One disadvantage of known segments is that they require a rather complex manufacturing process, and are thus costly and have too high overall weights.
Another disadvantage of known segments is that the position of the attachment zone of the actuation member, with respect to the point where it pivots with the subsequent segment, is not correlated to the mechanical resistance of the segment itself, to the size of the actuation member used and to the safety margins required. This entails the need to use actuation members with sizes that are not appropriate for the particular application on the articulated arm, and also the need to oversize the sections of particular portions of the segment, thus increasing its overall weight.
Furthermore, when they are closed on themselves, known articulated arms have a very large overall bulk, with the disadvantage that it is less easy to move and maneuver the vehicle on which the articulated arm is mounted.
U.S. Pat. No. 5,316,709 discloses an arm for an excavator comprising an articulated segment in which there are two attachment zones, the first to the segment connected to the vehicle, the second to attach the actuator that drives the excavation element. The two attachment zones are substantially at the same height in correspondence with two protruding parts of the profile of the articulated segment, which has a section shape like a double triangle with coinciding bases.
The section shape described in US'709 is not suitable to solve the disadvantages indicated above, in particular the resistance to point-by-point stresses deriving from the drive of the actuators and the reduction in bulk during the transfer and movement of the vehicle.
One purpose of the present invention is to obtain a segment of an articulated arm which is simple to make, economical and which has a lower overall weight than known segments.
Another purpose is to obtain a segment of an articulated arm that is optimized in relation to mechanical resistance, to the size of the actuation member used and to safety requirements.
Another purpose of the present invention is to obtain an articulated arm comprising at least a segment of the above type in which its overall mechanical resistance and its overall size is optimized, at least in the transport configuration.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.